>Does1 Cor 7:17 have conditional force? Eij mh; eJkavstw/ wJ" ejmevrisen oJ
>kuvrio", e{kaston wJ" kevklhken oJ qeov", ou{tw" peripateivtw. Only, as the
>Lord has assigned to each one, as God has called each, in this manner let him
>walk. I am having difficulty making sense of the logical equivalent of "if
not
>B, then not A" if it does. This may be because of the hWS in the two
protases.
>If the hWS is dropped then the logical equivalent seems to be "if one does
not
>walk in this manner, then the Lord has measured to him and God has called
>him." But this does not make sense. Perhaps EI MH does not go with the hWS
>clauses and instead is the protasis to hOUTWS PERIPATEITW? But the logical
>equivalent is still evasive. Can anyone help with this?

There is a very good discussion of this in Robertson's Massive Yellow Tome,
starting at the bottom of page 1024, which is found in a section that
discusses lots of things that are pretty close to normal conditional
sentences, but aren't easy to read as such. (I read this yesterday because
I stumbled on the phrase EI DOQHSETAI THi GENEAi TAUTH SHMEION (Mark 8:12),
which threw me completely.)

In 1 Cor 7:17, EI MH does seem to be used as a fixed expression, meaning
"except". See 1 Cor 7:5; Ga 1:7,19; Ro 14:14; Mt 5:13; Mt 11:27; Mt 21:19
for further examples of this. Robertson says that this is also very common
in classical Greek.

I don't think you will easily coerce this into "if A then B" form, which is
necessary if you want to construct an "if not A then not B" statement.
Robertson treats this as an "elliptical condition", where the "if" clause
is not expressed, and presents his view of the history by which this usage
emerged. If he's right, then you have to infer your own A. However, I
suspect that there *is* no A that you can write into such a sentence
without changing its meaning, and I find it clearer to just treat EI MH as
a fixed expression that means "except".

Also, you should be aware that a lot has been written about the fact that
"if" in natural language does not mean the same as "if" in formal logic.
See, for instance, Paul Grice's "Studies in the Way of Words", which goes
into a brief history of this question. My own observation is this: the
mapping from natural language conditionals to formal logic is not well
defined, and in most cases there is no really good mapping. If you write a
syllogism in order to express the meaning of a natural language
conditional, then the syllogism generally omits some of the meaning that a
native speaker of the language might generally associate with the content
of the original sentence.